Preparation method of quinclorac

A technology of quinclorac and quinoline carboxylic acid, applied in the field of herbicides, can solve the problems of unfavorable cleaning process production, inability to recycle and apply, and high cost of three wastes treatment

Active Publication Date: 2020-07-07
NUTRICHEM LAB CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The reaction raw materials used in the preparation method of quinclorac involved in the above two patent applications are the same, and are all synthesized 3,7-dichloro-8-quinoline carboxylic acid by the method of first chlorination and oxidation. A large amount o...

Method used

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  • Preparation method of quinclorac

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[0024] The invention provides a kind of preparation method of quinclorac, wherein, the method comprises the following steps,

[0025] 1) Using N-hydroxyphthalimide compounds and azobisisobutyronitrile as catalysts and oxygen as an oxidant to oxidize 7-chloro-8-methylquinoline to obtain 7-chloro-8-quinoline morphine carboxylic acid;

[0026] 2) Using azobisisobutyronitrile as a catalyst, chlorinating 7-chloro-8-quinolinecarboxylic acid and chlorine to obtain 3,7-dichloro-8-quinolinecarboxylic acid.

[0027] According to the method of the present invention, by using N-hydroxyphthalimide compounds and azobisisobutyronitrile as a catalyst, oxygen is used as an oxygenant to oxidize 7-chloro-8-methylquinoline, which can The generation of waste acid and waste water in the oxidation process can be avoided, and 7-chloro-8-quinolinecarboxylic acid can be obtained with low reaction temperature, simple post-treatment and high yield.

[0028] In step 1), the amount of the N-hydroxyphthal...

Embodiment 1

[0043] 1) In reactor A, add 200 grams of ice water, slowly add 600 grams of concentrated sulfuric acid, then add 423 grams of 3-chloro-2-methylaniline, 1 gram of sodium iodide, and slowly add 290 grams of glycerin at 120°C , The dropwise addition was completed in 4 hours, and the temperature was kept at 140° C. for 3 hours. After the reaction finishes, cool down to 30°C, add 200 grams of water, 1200 grams of sherwood oil (boiling range 90-120°C), adjust the pH to 9~10 with 20% by weight of sodium hydroxide solution, then heat up to 80°C for 1 Hours, static layering, camera precipitated until no fraction was formed to obtain 497.7 g of 7-chloro-8-methylquinoline with a content of 98.3% by weight and a yield of 92.1%.

[0044] 1 H-NMR(500MHz,d6-DMSO):δ8.991-8.98(dd,1H,J 1 =1.5Hz,J 2 =1.5Hz), 8.405-8.386(dd,1H,J 1 =1.5Hz,J 2 =1.5Hz)7.874-7.857(d,1H,J=8.5Hz),7.64-7.622(d,1H,J=9Hz),7.596-7.572(dd,1H,J 1 =4Hz,J 2 = 4Hz), 2.799(s, 3H). LCMS (M+1): 178.1.

[0045] 2) In react...

Embodiment 2

[0050] 1) In reactor A, add 200 grams of ice water, slowly add 600 grams of concentrated sulfuric acid, then add 423 grams of 3-chloro-2-methylaniline, 1 gram of sodium iodide, and slowly add 290 grams of glycerin at 120°C , The dropwise addition was completed in 4 hours, and the temperature was kept at 140° C. for 3 hours. After the reaction finishes, cool down to 30°C, add 200 grams of water, 1200 grams of sherwood oil (boiling range 90-120°C), adjust the pH to 9~10 with 20% by weight of sodium hydroxide solution, then heat up to 80°C for 1 Hours, static layering, camera precipitation until no fraction is generated, 497.7 grams of 7-chloro-8 methylquinoline (confirmed by nuclear magnetic and mass spectrometry data to obtain 7-chloro-8 methylquinoline), content 98.3% by weight , yield 92.1%.

[0051] 2) In reactor B, add 300 grams of 7-chloro-8-methylquinoline, 300 milliliters of acetonitrile solution, 2.76 grams of N-hydroxyphthalimide, and 4.17 grams of azobisisobutyronitr...

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Abstract

The invention relates to the field of herbicides, and discloses a preparation method of quinclorac, which comprises: 1) adopting an N-hydroxyphthalimide compound and azodiisobutyronitrile as catalysts, adopting oxygen as an oxidizing agent, and oxidizing 7-chloro-8-methylquinoline to obtain 7-chloro-8-quinoline carboxylic acid; and 2) by taking azodiisobutyronitrile as a catalyst, carrying out chlorination reaction on 7-chloro-8-quinoline carboxylic acid and chlorine to obtain 3,7-dichloro-8-quinoline carboxylic acid. By means of the method disclosed by the invention, the generation of a largeamount of waste acid and wastewater in a synthesis process can be reduced, and the product yield of quinclorac can be increased.

Description

technical field [0001] The invention relates to the field of herbicides, in particular to a preparation method of quinclorac. Background technique [0002] Quinclorac, also known as 3,7-dichloro-8-quinoline carboxylic acid, is a special selective herbicide for preventing and treating barnyardgrass in paddy fields, and belongs to hormone-type quinolinic acid herbicides. Its structural formula is as follows: [0003] [0004] The herbicide has the advantages of good weeding effect, safety to crops, and the application time is not limited by the growth stage of weeds, etc., and is widely recognized by the market. [0005] Patent application CN101851197A discloses a method for synthesizing and refining dichloroquinoline carboxylic acid, using m-chloro-o-toluidine and glycerol as raw materials to prepare 7-chloro-8-methylquinoline, and then 7-chloro-8-methylquinoline 3,7-dichloro-8-chloromethylquinoline is chlorinated with chlorine gas, and finally 3,7-dichloro-8-chloromethyl...

Claims

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Application Information

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IPC IPC(8): C07D215/48
CPCC07D215/48
Inventor 王晓刚涂俊清路风奇付裕张艳芳霍世勇
Owner NUTRICHEM LAB CO LTD
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